Improvement in holders for screw-threading dies



2 Sheets-Sheet1..

can, MURGAN. Holdersl for Screw-Threading Dies. No.155588, PatentedOct.6,1874.

, "lf-EWI@ Izzi/anion UNITED STATES CHARLES H. MORGAN,

PATENT OEETCE. ff

OF CLEVELAND, OHIO.

Specification forming part'of Letters Patent No. 155,588, dated October6, 1374 application led Y A May '4, 1s14.`

To all whom it may concern: Y

Be it known that I, CHARLES H. MORGAN, of Cleveland, in the county ofCuyahoga and State of Ohio, have invented a certain new and ImprovedHolder for Die for Cutting Bolts, of whichfthe following is a completedescription, reference being had to the accompanying draw-- ings, makinga part of this specification.

Figures 1 and 4 are' side views of the dieholder. Fig. 2 is a plan view.Fig. 3 is a front view. Fig. 5 is a longitudinal vertical section. Y.

Like Aletters of referencefrefer to' like parts in the several views.

This invention is for holding the dies for cutting screw-bolts; and thespecial object of the invention is to open the'dies at the moment theyhave done cutting, so that the bolt can be withdrawn from them withoutmarking the thread.

Of the construction and operation of the aforesaid invention thefollowing is a full detailed description. 'l A In the drawings, Arepresents a stem, wherebythe holder is secured in the screwmachinelathe by inserting the stem in the mandrel or in the turret thereof. Tosaid stem is hinged a pair of jaws, B C, at a a. The two jaws are openedby springs D E, Figs. 4 and 5, and are closed by a yoke, F, Figs. l and3. The lower end of the yoke is pivoted in the sides of the lower jaw,whereas the upper end extends across the upper one, asfwilljbe seen inFigs. 2 and 3. On the inside of each side of the yoke is secured ablock, G H, Fig. 3. Said blocks are adjustable vertically by having thebolt whereby they are secured to the yoke fitted in a slot. Fixed to thetop of the jaw B, and directlyunder the blocks above referred to, areblocks I, Fig.`3, upon which the blocks Gr H respectively rest when thetwo jaws are closed, as shown in said Fig. 3. In the stem A is looselyfitted a rod, J, Fig. 5, to the inner end of which is secured across-head, K, which is attached to the yoke by links L,

one on each side of the jaws, as seen in Fig..

2. Around the rod J is coiled a spring, M, back of the crossfhead, asshown in Fig. 5, the purpose of which will presentlybe shown. N, Figs. land 2, are links, the ends of which are pivoted to the side of the jawC. The upper as follows: As above said, the die-holder is held in thelathe or screW-machinevby inserting the stem A into the turret thereof.The

dies cl c, Fig. 3, are'held in the jaws by screws n o. The position ofthe jaws and the dies therein, as shown in Fig. 1, is such as when theyare closed for the admissionv of the bolt. This position of the jaws ismaintained by the yoke F, which, to that end, is pushed forward" so faras to allow the blocks G H to rest upon the blocks or steps I, therebyclosing the die for cutting the bolt. As the die-holder and dies revolve(or, instead thereof, the bolt may revolve and the holder remain still)the end of the bolt is inserted in the die and the thread thereon out.When the end of the bolt, on being drawninto the die, reaches the end ofthe rod J, the pressure of the bolt forces back the rod, together withthe cross-head to which it is connected. This backward movenient of thecross-head draws back the yoke F so far as to cause the blocks G H toslip from off the steps I, at which moment the jaws and diesspring openby the recoil of the springs D E placed between them, thereby releasingthe bolt from the dies, which is now with drawn for the insertion ofanother bolt. To this end the dies are again closed by means of thehandle P, which the operator pulls forward, thereby bringing the head Qthereof down upon. the top of the jaw B, which will draw the two jawstogether, and which are retained thus by the yoke F, at this momentpushed forward by the reaction of the spring M so far as to bring theblocks again upon the steps I, thus clamping the dies together, butwhich yoke is again pushed back by the bolt on coming in contact withthe end of the rod J, pushing the blocks from oif the steps, allowingthe dies to instantly open for the withdrawal of the bolt.

It will be observed that the two jaws have not one common pivoted point,but that each one has its own, and that placed distant from the centralline a; x of the holder. The pur* pose of placing the pivotal points ofthe jaws eccentric tosaid line is to cause the jaws to open nearer aright angle to the line of the cut or threaded bolt than they would dohad the. two jaws a common pivotal point. By this means the thread ofthedies will leave the thread of the bolt almost at right angle, and thusavoid all possible marring of the thread by contact therewith aftercutting.

In consequence of having each jaw move on its own pivotal point itbecomes highly important that the two jaws should move exactly at thesame time, and at the same distance in such time, toward the centralline aa; otherwise the dies will not close evenly together, inconsequence of the end chasing of the jaws, should one jaw, for anyreason, not move so fast as the other. To guard against this end chasingor longitudinal movement of the jaws that may possibly take place in theclosing together of the jaws is the purpose of the screws h. The ends ofsaid screws are cone-shaped, and made to t into correspondingcone-shaped holes z', Fig. 2, in the upper jaw. Said holes are indicatedby the dotted lines o', Fig. 1. Said holes are lined with a steel bush,and the ends of the screws enter them on closing the jaws, which serve,in the character of dowelpins, to prevent end chasing of the jaws uponeach other.

The purpose of having the blocks G H adjustable. is to permit of thedies to be opened more or less wide, so that diiierent-sized bolts maybe cut with them.

The rod J is adjustable in the cross-head K to allowof its being pushedthrough the head more or less, and thereby regulate the length of thethread to be cut on the bolt. Thus, if a short length of thread isrequired onv the bolt, the rod is pushed in farther, so that the end ofthe bolt will strike it by the time that the length of thread is cut,and thereby open the dies in the manner as aforesaid.

What I claim as my invention, and desire Vto secure by Letters Patent,is-

l. The yoke F, links L, cross-head K, rod J, and spring M, and springsI) E, in combination with the jaws B C, in the manner substantially asdescribed, and for the purpose set forth.

2. rEhe adjustable blocks G H and steps I I, in combination with theyoke F and jaws B C, substantially in the manner as described, and forthe purpose specified.

3. The dowel-screws h h, in combination with the cone-shaped holes i andthe jaws B G, substantially as described, and for the purpose

